My work on parental investment, and the trade-offs individuals face between investment in children versus mating effort or in themselves, includes:

comparing investments by stepfathers and genetic fathers, in Cape Town, South Africa and Albuquerque, New Mexico (USA)

examining paternity confidence (whether men think they are the fathers of the children attributed to them) and the implications for men’s investments in children (as well as in the relationship with the child’s mother)

examining the factors that influence whether a man is named as the father on a child’s birth certificate, and the implications for the child’s well being

explaining the very low fertility observed in post-demographic transition societies such as the United States

trade-offs between paying child support and men’s ability to subsequently father children or remarry

time use among men and women in subsistence ecologies

male allocare and life history traits among non-human primates (with Allie Sheldon)

Much (though by no means all) of my research draws upon life history theory, the branch of evolutionary biology that focuses on the timing of sexual maturity, reproduction, and mortality in the contexts of trade-offs between investing in offspring, in relationships with mates, and in oneself. A good introduction to life history theory can be found here.